Last revised by Tim Luijkx on 23 Jul 2019

The cuneus (plural: cunei) is a wedge-shaped region on the medial surface of the occipital lobe.

Anterosuperiorly the parieto-occipital sulcus separates the cuneus from the precuneus of the parietal lobe.

Posteroinferiorly the cuneus abuts the calcarine sulcus which separates it from the lingual gyrus 1.

The parieto-occipital sulcus and calcarine sulcus join to form a "Y".

Blood supply to the cuneus is via the calcarine artery and parieto-occipital artery. The proportion varies from person to person and either artery can be the major source of perfusion 2.

Fibers of the superior optic radiation corresponding to the inferior quadrant of the visual field synapse on the cuneus 3.

Magneto encephalographic (MEG) measurements of occipital cortical signals have shown that the anteromedial cuneus activates almost simultaneously with the primary visual cortex (3-4 ms delay) in response to a visual stimulus and may act to modulate signals traveling from the primary visual cortex to the extrastriate cortices 4.

Lesions of the cuneus result in an inferior contralateral quadrantanopia 3.

Beyond its role in vision, a reduction of cortical thickness of the cuneus has also been associated with the pathogenesis of trigeminal neuralgia 5, as well as the development of psychosis in patients with a history of herpes simplex virus type 1 infection 6

An MRI study found that thinning of posterior cortical regions, including the cuneus, is closely correlated with the occurrence and severity of visual hallucinations in dementia with Lewy bodies 7.

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Cases and figures

  • Figure 1: cuneus
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  • Figure 2: relations
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